1. Field of the Invention
This invention relates to the art of soap making, and more particularly to a process for elimination of wet cracking and stress cracking in soap.
2. Description of the Prior Art
New test methods for evaluating soap bar and cake wet cracking problems are disclosed in U.S. Pat. No. 4,147,053. Based on the application of these new tests and the observations of the results, it has been discovered that toilet soap bars made by the single extrusion process showed a somewhat laminar or parallel crack pattern in the cross sectional test. These bars, in general, did not develop severe wet surface cracks when subjected to the wash room usage test. Contrastingly, bars made by the dual extrusion process have a generally non-parallel crack pattern with radical spurs radiating always preferentially to one side and across the short axis of the bars. These bars, when field tested, would consistently develop severe wet surface cracks always significantly more on one side than the other. The prior art dual extrusion process leads to problems in the formation of wet surface cracks during use of the bars since the stress pattern of the bars is such that upon use with water, the forces which tend to hold the lamina in the bar together are weakened, and, hence, there was a need to devise a means for imparting a laminar or parallel crack pattern to finished soap bars made via the dual extrusion process.
In the past, high moisture containing soap bars have been produced by plodding a soap mass and forcing it through a compression cone with a dual extrusion nozzle so that the two streams of plodded soap which may be divided into plodder soap blanks or billets which can be fed into a duplopress to provide increased line speed and efficiency. However, changes in the soap formula (i.e., lowering the moisture) and different selections of bar shapes generally result in finished soap bars with unusual and excessive surface cracking on the faces of the bars with one side having a more pronounced cracking pattern than the other. This problem is directly related to the dual extrusion soap plodding process and the conventional method of pressing the plodder soap blanks or billets on their internal cut faces and external cut faces.